Enhanced Perovskite Solar Cells Efficiency via Electric Field-induced Approach.

: The stability issue hinders the commercialization of the perovskite solar cells (PSCs), which is widely recognized. The efficiency generally decreases over time during the working condition. Here we report an efficiency enhancement phenomenon of PSCs in the stability test at maximum power point, which is speculated to be related to the electric field-induced ion migration. The defect density and efficiency-related parameters were traced in-situ by admittance spectroscopy (AS) and transient photovoltage (TPV) when the cell works under bias voltage. The performance enhancement was revealed to be attributed to the reduction of the cell defects owing to ion migration. 22.3% efficiency can be achieved after the bias voltage was kept for 8 hrs. These findings suggest that ion migration is a double-edged sword that affects the electrical stability of PSCs, which presents a potential approach to improve the device's stability by appropriately controlling the defect states.